Symfony Application Change default culture

apps/frontend/config/settings.yml
all:
  .settings:
      defaut_culture: vi

Article (I18N: name, body)

In action:
$article = ArticleTable::getInstance()->find(1987);
if ($article !== false) {
  $this->getUser()->setCulture($unknownLang);
  $name = $article->getName(); # will return $vietnameseName (I am using Diem CMF; check function getI18nFallback in file dmDoctrineRecord.php)
  $englishName = $article->Translation['en']->name;
  $vietnameseName = $article->Translation['vi']->name;
}